Power-transmission mechanism



F. V. DONALD POWER TRANSMI S S ION MECHANI SM Jan, 1, 1924 2 Sheets-Sheet 1 Filed 001?. 24, 1921 Jan. 1,

F. V. DONALD POWER TRANSMISSION MECHANISM Filed 24. 1921 2 Sheets-Sheet 3 Patented Jan. 1, 1 924.

m an 'srA ronansrv. DONALD, or MINNEAPCLIS,M INNESOTA, nssrenon TO GI so-N MANUEAC- ATEN -T 05H) Tun-me cog, 'orronrwasnrnerou, iscons n, A conroaarron or WISCONSIN.

rownnrrnansmrssron -MECEANISM, s

Application filed October 24, 1921. SerialfNoi 509,873.

To alle'who' m it may concerns ,Be; it known thatl, FORREST V. DONALD, a citizen of theUnited States, residing at Minneapolis, in the county of Hennepin and 1 State of Minnesota, have invented certain new and useful Improvements in Powerlowing is a specification Transmission Mechanism, of which thefol mission mechanism, Y 1

In thls particular instance the inventlon s illustrated in connection, with a "garden power propelledground working implement; 1

lt will be understood that the inventionis not limited to such, application 1fO1'fit may be used generally in connection, with the transmission of power. However, in referring more vspecifically tov power propelled implements, such as garden tractors, heretofore which pinionsembodied ratchet mechanism permitting only the transmission of power for driving the traction wheels ina forward direction,-that is-Jtosay, such ratchet mechanism would not permit the traction wheels tobe moved in a direction permitting ,the

backing of the tractor. It is particularly desirable that such-traction wheels should be permitted to rotate in a rearward directionto facilitate'the steering of the tractor, and more particularlyito' freely permit short turning of the latter. 7

Furthermore, in tractors includingratchet mechanism, as above described, it ispossible for the tractor to run away in going down hill, because the traction wheels, under such I circumstances, are net positively connected with the enginerin ,ja manner such. that the engine is driven as a compressor by thetraction wheels to act as a brake. 7

Accordingly, .oneobject of my presentin vention isto improve j power transmission mechanism-Which will permit certain relative movements between the parts thereof to facilitate the efiicient operation of mechanism' of whichlgit forms apart in a combination.

Another object is to provide an improved power transmission mechanism for tractors which will permit easy steering and turnmg of the tractor.

Another object is to provide transmission .Th's invention relates, to power trans- I mechanism for tractors between the traction wheels and the engine which ;will permit turning movements ofthel tractor and also m aintaln a controlled connectlon between v the eng ne and tractlon cwheelsin, a manner,

such that it is impossible; for, the tractor to run away when operating on ,a down grade.

These and other objects are, accomplished by means of the arrangement disclosed on the/accompanying sheets of drawings, in

which,

.Figure 1 is a side elevationof a garden tractor embodying my invention;

Figure2 is a fragmentarytop planview, of the same and Figure 3 is a detail sectional .view illus-Q trating the main part of my improved power transmiss on mechan sm.

The various novel features "er my invention will be apparent from the following description and drawings, and will be particularly pointed out inthe appended claims, I 1

Referring to the figures of the drawingsy ventionin connection with a tractor }culti it will be noted that I have disclosed my'in- 80 vatorsuch as that shown in myco-pending 7 application, Serial No. 499,432, filed Sepi stember 9, 1921. Thistractor cultivator-inf cludes; a frame 10- carrying an engine 11, and carried by two traction wheels 12 which are mounted upon opposite ends of an axle I 13. Connected to the forward portion 14 of themain frame structure is the tool carrying frame 15 which carries any suitable cultivat ing tools, such as scrapers 16 and shovels 17, the rear end of the tool carrying frame being supported by gauge wheels 18.

Theiengine 11 is operatively connected to the traction wheels 12 for propelling the tractor andincludes' a crank shaft 19, upon one end of which is mounted a sheave 20 around which passes a transmission belt 21. This beltalso passes around a split sheave having two annular relatively movable parts 22 and 23, best shown in Figure The outer portions oftheinward adjacent faces of the sheave members 22 and-23 diverge radiallyoutwardly to form a V-shaped groove'24 for the reception of the ing belt 21.

Heretofore it has been similarly shaped drivthe practice in this general type of machine to have a solid one-piece sheave, instead of the multiple? piece sheave here shown, mounted upon a shaft to the opposite ends of which pinions are rigidly connected, said pinions in turn ment of the latter.

being operatively connected to the traction wheels of the tractor for propelling thelatter. With such an arrangement there is a' ratchet and pawl mechanismassociated with the pinions which will permit forward driving ofthe tractor but no rearward move- As a result thereof steering is not accomplished as easily as might be, and turning the tractor short iira small space is almost impossible because one or the other of the wheels-cannot move rearward'ly vto facilitate shortturning and, as mentioned h'ereinabove, with such'a ratchet and pawl arrangementthere' is no positive hill it will be impossible for it to runaway for the'reason that'the engine will then be driven asa compressor. Referring again to Figure 3 of'the drawings, it will be noted that the two parts'22 and 23 of the sheave are mounted upon a shaft 25, one part 22 being loosely or rotatably mounted upon said shaft and the other sheave part 23 being secured'tothe shaft by a key'26, the shaftbeing supported in a lon'g bearing member 27 which may be secured 'tothe'engine fram'eor any other portion of the tractor by perforated brackets 28 and bolts 29; 'Integrally 'formed or otherwise'secured to the sheave part 22 isa sprocket wheel 30 aroun'dwhich passes a chain 31 which also" passes around a relatively large sprocket wheel 32 opera-'- tively connected to one of the traction wheels 12 for transmitting propelling power thereto. Keyed'to the opposite end of the shaft 25 is another sprocket wheel 33 around which passes a chain 34 which in turn passes around another sprocket wheel 32 operatively associated with the other traction wheel 12 for transmitting propelling" power' thereto. Accordingly, it is seen that propelling power is transmitted from the engine 11 through a sheave having two independently and relatively movable parts 22' and 23, and that the driving belt 21 when in operativddriving posi tion engages both sheave parts 22 and 23. Under normal driving conditions, the

driving belt 21 is maintained taut by a movably mounted idler sheave 35 which When be controlled in any suitable manner. the driving belt 21 is in operative position, th'at'is, in driving engagement with respect to both sheave parts 22' and 23 both traction 7 her loosely mounted'wn said'sh-aftfand eratively connected to one of said "traction 130 wheels receive propelling power. If it is desired to steer: the"tra'ctor or to turn same, and especially within a" small space, I the driving belt 21 is first slackened, whereupon the tractor may be-turned about-ina relatively small space,- lsuch as 1a two; wheel cart wouldbe, the samebeing permitted as aresult 'of oneofthe wheels moving rearwardly and the other one moving forwardly. The relatively'opposite turning movements of these traction wheels is permitted because of the permissible relative movemem-=- be tween t'he sheave parts 22am 23 Furthermore; with the' 'belt inoperative or driving position, it"is apparenfithat if thetractor f" is "moving down hill at greater speed" thhn 5 theengine'wouldbe 'driving i the trea es;

wheelswould their be i iving theengine s-- a compressor, the en vneuirder suchi oh?" 7 dition's acting: as aj bra'ke te prevent the tractor from running away? f c It will be a preciated tlratthistransmis- S1011? mechanism may beu'seu in combinations other than in-a" tractor transmission systeia;

It is my intention to we all md-ifiCations of the? invention failing -?w'i'thiii the spirit'andscope of the' following claims Iclaimr f V 1 1.- In a tractor,'fthe\1 combination of aplurality of traction wheels; an engine' f propelling' same," and power 'tran'smis's on mechanism interposed therebetween inch-1d ing a sheave"having tWoarts for jointly receiving powertransmission belt; eas er? said sheave part-stung operativelyl co" 00 nected me one jQr said traetion wheeis aea the other sheave 'part being operatively, connected to another 'tfactionwheel,- sa'd sheave parts" beingfcapable of? relative m tative movement when th'e belt- 1 slackened loe to permit a turning movement of tractor? 25111 atractor," the combination' oft I tion wheels, means 1 for 'd'riivin"g said traetican 1 wheels; a power 'tiansmis'siori mechanis therebetweeir including" a"-- shaft, a s hea 1 comprising two separate parts mounted on said shaft, one of 'said sheaye*parts -being loosely'mounted on said shaft and operative ly connected' to one of said 5 tra-ction whf'eels and the other sheave-part1 being 'keyd said 'sh aftandoperativel y connected t a other of said traction -whee1spower being'g1 transmitted through saidsheave "pantsto I said traction wheels'when the b hlt 'isf t,ig}- i; v on'said sheave, said sheavepartsibeiirg a pable of relative rotativeniovement for per mitting a steeringmovement 'of the'tractor when the belt is loose-onsai-d shearer 3'; In a tractor, the conibination or eplurality of traction'whe'elsj meansfor driv-f 7 ing same, a transmission,mechanisminter posed between saidfdriving' means and traittion wheelsincluding'ashaftfasheavem I wheels, another sheave member secured to being free to have relative movement with said shaft and operatively connected to respect to each other when the belt is another one of said traction wheels, said slackened to facilitate turning of the 10 sheave members being arranged adjacent tractor. a 7

each other to receive a belt therebetween for Signed at Port Washington, Wisconsin, transmitting power to said traction wheels this18th day of October, 1921.

when the belt is taut, saidsheavemembers FORREST V. DONALD. 

